Butters pays a girl to get his first kiss. A man now, he thinks he is; And, so he needs to make money to support his wife and kids. So, he sets up a company of selling kisses with girls from school; and @ school. Kyle tries to stop him but gets bitch smacked for $100. Butters learns he is a P.I.M.P. and goes to a P.I.M.P. Convention to learn tools of the trade from other P.I.M.P.'s South Park Sheriff goes undercover as a prostitute to uncover the sex ring, but he takes his cover a little to seriously. Then when the Sheriff agrees to marry his ex-P.I.M.P. Butters decides to retire after making millions off his bitches because love is worth more than $5.
Now all that said? I think this is the funniest, and best episode, this season; Because, it had no real point to it other than to make fun of Butters. Though him paying the school-mate $100 to 'protect' him from Kyle was the best part. The off handed way Butters took to being a P.I.M.P. was just made the episode that some kind of awesome.